On Mon, 8 Dec 1997, Gene wrote:

> If:  X = the set of all things consumed by p-man.
>      Y = the set of all things safe/healthy to consume.
>
> We will agree that all members of the set X *are* contained
> within the set of Y.  However, that does not logically mean,
> imply, or even suggest that all members of Y *are* contained
> in the set comprising X.

Actually, even the assertion that all X are Y can be questioned.
It is based on the assumption that human beings have not become
*disadapted* to anything in X during historical times.  There is
some reason to doubt this.  With respect to other phenotypic
traits, for example, it is obvious that many human beings are now
disadapted to life in the African grasslands where prehistoric
humans lived for very long periods of time.

Karsten Andersen's massive cholesterol response to the all-meat
diet in the 1928 Bellevue experiment with W. Stefansson strongly
suggests that he, unlike Stefansson, was disadapted to that diet.
The fact that his cholesterol normalized quickly after the
experiment was ended provides further support for that
conclusion.

So, in addition to recognizing that not all Y are necessarily X,
we have to be alert to the fact that not all X are necessarily Y,
even though membership in X offers good prima facie evidence of
membership in Y.

Todd Moody
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